/*
 * Copyright © 2014-2017 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */
#include <linux/debugfs.h>
#include <linux/relay.h>
#include "i915_drv.h"

static void guc_log_capture_logs(struct intel_guc *guc);

/**
 * DOC: GuC firmware log
 *
 * Firmware log is enabled by setting i915.guc_log_level to non-negative level.
 * Log data is printed out via reading debugfs i915_guc_log_dump. Reading from
 * i915_guc_load_status will print out firmware loading status and scratch
 * registers value.
 *
 */

static int guc_log_flush_complete(struct intel_guc *guc)
{
        u32 action[] = {
                INTEL_GUC_ACTION_LOG_BUFFER_FILE_FLUSH_COMPLETE
        };

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

static int guc_log_flush(struct intel_guc *guc)
{
        u32 action[] = {
                INTEL_GUC_ACTION_FORCE_LOG_BUFFER_FLUSH,
                0
        };

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

static int guc_log_control(struct intel_guc *guc, u32 control_val)
{
        u32 action[] = {
                INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING,
                control_val
        };

        return intel_guc_send(guc, action, ARRAY_SIZE(action));
}

/*
 * Sub buffer switch callback. Called whenever relay has to switch to a new
 * sub buffer, relay stays on the same sub buffer if 0 is returned.
 */
static int subbuf_start_callback(struct rchan_buf *buf,
                                 void *subbuf,
                                 void *prev_subbuf,
                                 size_t prev_padding)
{
        /* Use no-overwrite mode by default, where relay will stop accepting
         * new data if there are no empty sub buffers left.
         * There is no strict synchronization enforced by relay between Consumer
         * and Producer. In overwrite mode, there is a possibility of getting
         * inconsistent/garbled data, the producer could be writing on to the
         * same sub buffer from which Consumer is reading. This can't be avoided
         * unless Consumer is fast enough and can always run in tandem with
         * Producer.
         */
        if (relay_buf_full(buf))
                return 0;

        return 1;
}

/*
 * file_create() callback. Creates relay file in debugfs.
 */
static struct dentry *create_buf_file_callback(const char *filename,
                                               struct dentry *parent,
                                               umode_t mode,
                                               struct rchan_buf *buf,
                                               int *is_global)
{
        struct dentry *buf_file;

        /* This to enable the use of a single buffer for the relay channel and
         * correspondingly have a single file exposed to User, through which
         * it can collect the logs in order without any post-processing.
         * Need to set 'is_global' even if parent is NULL for early logging.
         */
        *is_global = 1;

        if (!parent)
                return NULL;

        /* Not using the channel filename passed as an argument, since for each
         * channel relay appends the corresponding CPU number to the filename
         * passed in relay_open(). This should be fine as relay just needs a
         * dentry of the file associated with the channel buffer and that file's
         * name need not be same as the filename passed as an argument.
         */
        buf_file = debugfs_create_file("guc_log", mode,
                                       parent, buf, &relay_file_operations);
        return buf_file;
}

/*
 * file_remove() default callback. Removes relay file in debugfs.
 */
static int remove_buf_file_callback(struct dentry *dentry)
{
        debugfs_remove(dentry);
        return 0;
}

/* relay channel callbacks */
static struct rchan_callbacks relay_callbacks = {
        .subbuf_start = subbuf_start_callback,
        .create_buf_file = create_buf_file_callback,
        .remove_buf_file = remove_buf_file_callback,
};

static int guc_log_relay_file_create(struct intel_guc *guc)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        struct dentry *log_dir;
        int ret;

        if (i915.guc_log_level < 0)
                return 0;

        /* For now create the log file in /sys/kernel/debug/dri/0 dir */
        log_dir = dev_priv->drm.primary->debugfs_root;

        /* If /sys/kernel/debug/dri/0 location do not exist, then debugfs is
         * not mounted and so can't create the relay file.
         * The relay API seems to fit well with debugfs only, for availing relay
         * there are 3 requirements which can be met for debugfs file only in a
         * straightforward/clean manner :-
         * i)   Need the associated dentry pointer of the file, while opening the
         *      relay channel.
         * ii)  Should be able to use 'relay_file_operations' fops for the file.
         * iii) Set the 'i_private' field of file's inode to the pointer of
         *      relay channel buffer.
         */
        if (!log_dir) {
                DRM_ERROR("Debugfs dir not available yet for GuC log file\n");
                return -ENODEV;
        }

        ret = relay_late_setup_files(guc->log.runtime.relay_chan, "guc_log", log_dir);
        if (ret < 0 && ret != -EEXIST) {
                DRM_ERROR("Couldn't associate relay chan with file %d\n", ret);
                return ret;
        }

        return 0;
}

static void guc_move_to_next_buf(struct intel_guc *guc)
{
        /* Make sure the updates made in the sub buffer are visible when
         * Consumer sees the following update to offset inside the sub buffer.
         */
        smp_wmb();

        /* All data has been written, so now move the offset of sub buffer. */
        relay_reserve(guc->log.runtime.relay_chan, guc->log.vma->obj->base.size);

        /* Switch to the next sub buffer */
        relay_flush(guc->log.runtime.relay_chan);
}

static void *guc_get_write_buffer(struct intel_guc *guc)
{
        if (!guc->log.runtime.relay_chan)
                return NULL;

        /* Just get the base address of a new sub buffer and copy data into it
         * ourselves. NULL will be returned in no-overwrite mode, if all sub
         * buffers are full. Could have used the relay_write() to indirectly
         * copy the data, but that would have been bit convoluted, as we need to
         * write to only certain locations inside a sub buffer which cannot be
         * done without using relay_reserve() along with relay_write(). So its
         * better to use relay_reserve() alone.
         */
        return relay_reserve(guc->log.runtime.relay_chan, 0);
}

static bool guc_check_log_buf_overflow(struct intel_guc *guc,
                                       enum guc_log_buffer_type type,
                                       unsigned int full_cnt)
{
        unsigned int prev_full_cnt = guc->log.prev_overflow_count[type];
        bool overflow = false;

        if (full_cnt != prev_full_cnt) {
                overflow = true;

                guc->log.prev_overflow_count[type] = full_cnt;
                guc->log.total_overflow_count[type] += full_cnt - prev_full_cnt;

                if (full_cnt < prev_full_cnt) {
                        /* buffer_full_cnt is a 4 bit counter */
                        guc->log.total_overflow_count[type] += 16;
                }
                DRM_ERROR_RATELIMITED("GuC log buffer overflow\n");
        }

        return overflow;
}

static unsigned int guc_get_log_buffer_size(enum guc_log_buffer_type type)
{
        switch (type) {
        case GUC_ISR_LOG_BUFFER:
                return (GUC_LOG_ISR_PAGES + 1) * PAGE_SIZE;
        case GUC_DPC_LOG_BUFFER:
                return (GUC_LOG_DPC_PAGES + 1) * PAGE_SIZE;
        case GUC_CRASH_DUMP_LOG_BUFFER:
                return (GUC_LOG_CRASH_PAGES + 1) * PAGE_SIZE;
        default:
                MISSING_CASE(type);
        }

        return 0;
}

static void guc_read_update_log_buffer(struct intel_guc *guc)
{
        unsigned int buffer_size, read_offset, write_offset, bytes_to_copy, full_cnt;
        struct guc_log_buffer_state *log_buf_state, *log_buf_snapshot_state;
        struct guc_log_buffer_state log_buf_state_local;
        enum guc_log_buffer_type type;
        void *src_data, *dst_data;
        bool new_overflow;

        if (WARN_ON(!guc->log.runtime.buf_addr))
                return;

        /* Get the pointer to shared GuC log buffer */
        log_buf_state = src_data = guc->log.runtime.buf_addr;

        /* Get the pointer to local buffer to store the logs */
        log_buf_snapshot_state = dst_data = guc_get_write_buffer(guc);

        /* Actual logs are present from the 2nd page */
        src_data += PAGE_SIZE;
        dst_data += PAGE_SIZE;

        for (type = GUC_ISR_LOG_BUFFER; type < GUC_MAX_LOG_BUFFER; type++) {
                /* Make a copy of the state structure, inside GuC log buffer
                 * (which is uncached mapped), on the stack to avoid reading
                 * from it multiple times.
                 */
                memcpy(&log_buf_state_local, log_buf_state,
                       sizeof(struct guc_log_buffer_state));
                buffer_size = guc_get_log_buffer_size(type);
                read_offset = log_buf_state_local.read_ptr;
                write_offset = log_buf_state_local.sampled_write_ptr;
                full_cnt = log_buf_state_local.buffer_full_cnt;

                /* Bookkeeping stuff */
                guc->log.flush_count[type] += log_buf_state_local.flush_to_file;
                new_overflow = guc_check_log_buf_overflow(guc, type, full_cnt);

                /* Update the state of shared log buffer */
                log_buf_state->read_ptr = write_offset;
                log_buf_state->flush_to_file = 0;
                log_buf_state++;

                if (unlikely(!log_buf_snapshot_state))
                        continue;

                /* First copy the state structure in snapshot buffer */
                memcpy(log_buf_snapshot_state, &log_buf_state_local,
                       sizeof(struct guc_log_buffer_state));

                /* The write pointer could have been updated by GuC firmware,
                 * after sending the flush interrupt to Host, for consistency
                 * set write pointer value to same value of sampled_write_ptr
                 * in the snapshot buffer.
                 */
                log_buf_snapshot_state->write_ptr = write_offset;
                log_buf_snapshot_state++;

                /* Now copy the actual logs. */
                if (unlikely(new_overflow)) {
                        /* copy the whole buffer in case of overflow */
                        read_offset = 0;
                        write_offset = buffer_size;
                } else if (unlikely((read_offset > buffer_size) ||
                                    (write_offset > buffer_size))) {
                        DRM_ERROR("invalid log buffer state\n");
                        /* copy whole buffer as offsets are unreliable */
                        read_offset = 0;
                        write_offset = buffer_size;
                }

                /* Just copy the newly written data */
                if (read_offset > write_offset) {
                        i915_memcpy_from_wc(dst_data, src_data, write_offset);
                        bytes_to_copy = buffer_size - read_offset;
                } else {
                        bytes_to_copy = write_offset - read_offset;
                }
                i915_memcpy_from_wc(dst_data + read_offset,
                                    src_data + read_offset, bytes_to_copy);

                src_data += buffer_size;
                dst_data += buffer_size;
        }

        if (log_buf_snapshot_state)
                guc_move_to_next_buf(guc);
        else {
                /* Used rate limited to avoid deluge of messages, logs might be
                 * getting consumed by User at a slow rate.
                 */
                DRM_ERROR_RATELIMITED("no sub-buffer to capture logs\n");
                guc->log.capture_miss_count++;
        }
}

static void capture_logs_work(struct work_struct *work)
{
        struct intel_guc *guc =
                container_of(work, struct intel_guc, log.runtime.flush_work);

        guc_log_capture_logs(guc);
}

static bool guc_log_has_runtime(struct intel_guc *guc)
{
        return guc->log.runtime.buf_addr != NULL;
}

static int guc_log_runtime_create(struct intel_guc *guc)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        void *vaddr;
        struct rchan *guc_log_relay_chan;
        size_t n_subbufs, subbuf_size;
        int ret;

        lockdep_assert_held(&dev_priv->drm.struct_mutex);

        GEM_BUG_ON(guc_log_has_runtime(guc));

        ret = i915_gem_object_set_to_wc_domain(guc->log.vma->obj, true);
        if (ret)
                return ret;

        /* Create a WC (Uncached for read) vmalloc mapping of log
         * buffer pages, so that we can directly get the data
         * (up-to-date) from memory.
         */
        vaddr = i915_gem_object_pin_map(guc->log.vma->obj, I915_MAP_WC);
        if (IS_ERR(vaddr)) {
                DRM_ERROR("Couldn't map log buffer pages %d\n", ret);
                return PTR_ERR(vaddr);
        }

        guc->log.runtime.buf_addr = vaddr;

         /* Keep the size of sub buffers same as shared log buffer */
        subbuf_size = guc->log.vma->obj->base.size;

        /* Store up to 8 snapshots, which is large enough to buffer sufficient
         * boot time logs and provides enough leeway to User, in terms of
         * latency, for consuming the logs from relay. Also doesn't take
         * up too much memory.
         */
        n_subbufs = 8;

        /* Create a relay channel, so that we have buffers for storing
         * the GuC firmware logs, the channel will be linked with a file
         * later on when debugfs is registered.
         */
        guc_log_relay_chan = relay_open(NULL, NULL, subbuf_size,
                                        n_subbufs, &relay_callbacks, dev_priv);
        if (!guc_log_relay_chan) {
                DRM_ERROR("Couldn't create relay chan for GuC logging\n");

                ret = -ENOMEM;
                goto err_vaddr;
        }

        GEM_BUG_ON(guc_log_relay_chan->subbuf_size < subbuf_size);
        guc->log.runtime.relay_chan = guc_log_relay_chan;

        INIT_WORK(&guc->log.runtime.flush_work, capture_logs_work);

        /*
         * GuC log buffer flush work item has to do register access to
         * send the ack to GuC and this work item, if not synced before
         * suspend, can potentially get executed after the GFX device is
         * suspended.
         * By marking the WQ as freezable, we don't have to bother about
         * flushing of this work item from the suspend hooks, the pending
         * work item if any will be either executed before the suspend
         * or scheduled later on resume. This way the handling of work
         * item can be kept same between system suspend & rpm suspend.
         */
        guc->log.runtime.flush_wq = alloc_ordered_workqueue("i915-guc_log",
                                                WQ_HIGHPRI | WQ_FREEZABLE);
        if (!guc->log.runtime.flush_wq) {
                DRM_ERROR("Couldn't allocate the wq for GuC logging\n");
                ret = -ENOMEM;
                goto err_relaychan;
        }

        return 0;

err_relaychan:
        relay_close(guc->log.runtime.relay_chan);
err_vaddr:
        i915_gem_object_unpin_map(guc->log.vma->obj);
        guc->log.runtime.buf_addr = NULL;
        return ret;
}

static void guc_log_runtime_destroy(struct intel_guc *guc)
{
        /*
         * It's possible that the runtime stuff was never allocated because
         * guc_log_level was < 0 at the time
         **/
        if (!guc_log_has_runtime(guc))
                return;

        destroy_workqueue(guc->log.runtime.flush_wq);
        relay_close(guc->log.runtime.relay_chan);
        i915_gem_object_unpin_map(guc->log.vma->obj);
        guc->log.runtime.buf_addr = NULL;
}

static int guc_log_late_setup(struct intel_guc *guc)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);
        int ret;

        lockdep_assert_held(&dev_priv->drm.struct_mutex);

        if (!guc_log_has_runtime(guc)) {
                /* If log_level was set as -1 at boot time, then setup needed to
                 * handle log buffer flush interrupts would not have been done yet,
                 * so do that now.
                 */
                ret = guc_log_runtime_create(guc);
                if (ret)
                        goto err;
        }

        ret = guc_log_relay_file_create(guc);
        if (ret)
                goto err_runtime;

        return 0;

err_runtime:
        guc_log_runtime_destroy(guc);
err:
        /* logging will remain off */
        i915.guc_log_level = -1;
        return ret;
}

static void guc_log_capture_logs(struct intel_guc *guc)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);

        guc_read_update_log_buffer(guc);

        /* Generally device is expected to be active only at this
         * time, so get/put should be really quick.
         */
        intel_runtime_pm_get(dev_priv);
        guc_log_flush_complete(guc);
        intel_runtime_pm_put(dev_priv);
}

static void guc_flush_logs(struct intel_guc *guc)
{
        struct drm_i915_private *dev_priv = guc_to_i915(guc);

        if (!i915.enable_guc_submission || (i915.guc_log_level < 0))
                return;

        /* First disable the interrupts, will be renabled afterwards */
        gen9_disable_guc_interrupts(dev_priv);

        /* Before initiating the forceful flush, wait for any pending/ongoing
         * flush to complete otherwise forceful flush may not actually happen.
         */
        flush_work(&guc->log.runtime.flush_work);

        /* Ask GuC to update the log buffer state */
        guc_log_flush(guc);

        /* GuC would have updated log buffer by now, so capture it */
        guc_log_capture_logs(guc);
}

int intel_guc_log_create(struct intel_guc *guc)
{
        struct i915_vma *vma;
        unsigned long offset;
        uint32_t size, flags;
        int ret;

        GEM_BUG_ON(guc->log.vma);

        if (i915.guc_log_level > GUC_LOG_VERBOSITY_MAX)
                i915.guc_log_level = GUC_LOG_VERBOSITY_MAX;

        /* The first page is to save log buffer state. Allocate one
         * extra page for others in case for overlap */
        size = (1 + GUC_LOG_DPC_PAGES + 1 +
                GUC_LOG_ISR_PAGES + 1 +
                GUC_LOG_CRASH_PAGES + 1) << PAGE_SHIFT;

        /* We require SSE 4.1 for fast reads from the GuC log buffer and
         * it should be present on the chipsets supporting GuC based
         * submisssions.
         */
        if (WARN_ON(!i915_has_memcpy_from_wc())) {
                ret = -EINVAL;
                goto err;
        }

        vma = intel_guc_allocate_vma(guc, size);
        if (IS_ERR(vma)) {
                ret = PTR_ERR(vma);
                goto err;
        }

        guc->log.vma = vma;

        if (i915.guc_log_level >= 0) {
                ret = guc_log_runtime_create(guc);
                if (ret < 0)
                        goto err_vma;
        }

        /* each allocated unit is a page */
        flags = GUC_LOG_VALID | GUC_LOG_NOTIFY_ON_HALF_FULL |
                (GUC_LOG_DPC_PAGES << GUC_LOG_DPC_SHIFT) |
                (GUC_LOG_ISR_PAGES << GUC_LOG_ISR_SHIFT) |
                (GUC_LOG_CRASH_PAGES << GUC_LOG_CRASH_SHIFT);

        offset = guc_ggtt_offset(vma) >> PAGE_SHIFT; /* in pages */
        guc->log.flags = (offset << GUC_LOG_BUF_ADDR_SHIFT) | flags;

        return 0;

err_vma:
        i915_vma_unpin_and_release(&guc->log.vma);
err:
        /* logging will be off */
        i915.guc_log_level = -1;
        return ret;
}

void intel_guc_log_destroy(struct intel_guc *guc)
{
        guc_log_runtime_destroy(guc);
        i915_vma_unpin_and_release(&guc->log.vma);
}

int i915_guc_log_control(struct drm_i915_private *dev_priv, u64 control_val)
{
        struct intel_guc *guc = &dev_priv->guc;

        union guc_log_control log_param;
        int ret;

        log_param.value = control_val;

        if (log_param.verbosity < GUC_LOG_VERBOSITY_MIN ||
            log_param.verbosity > GUC_LOG_VERBOSITY_MAX)
                return -EINVAL;

        /* This combination doesn't make sense & won't have any effect */
        if (!log_param.logging_enabled && (i915.guc_log_level < 0))
                return 0;

        ret = guc_log_control(guc, log_param.value);
        if (ret < 0) {
                DRM_DEBUG_DRIVER("guc_logging_control action failed %d\n", ret);
                return ret;
        }

        if (log_param.logging_enabled) {
                i915.guc_log_level = log_param.verbosity;

                /* If log_level was set as -1 at boot time, then the relay channel file
                 * wouldn't have been created by now and interrupts also would not have
                 * been enabled. Try again now, just in case.
                 */
                ret = guc_log_late_setup(guc);
                if (ret < 0) {
                        DRM_DEBUG_DRIVER("GuC log late setup failed %d\n", ret);
                        return ret;
                }

                /* GuC logging is currently the only user of Guc2Host interrupts */
                gen9_enable_guc_interrupts(dev_priv);
        } else {
                /* Once logging is disabled, GuC won't generate logs & send an
                 * interrupt. But there could be some data in the log buffer
                 * which is yet to be captured. So request GuC to update the log
                 * buffer state and then collect the left over logs.
                 */
                guc_flush_logs(guc);

                /* As logging is disabled, update log level to reflect that */
                i915.guc_log_level = -1;
        }

        return ret;
}

void i915_guc_log_register(struct drm_i915_private *dev_priv)
{
        if (!i915.enable_guc_submission || i915.guc_log_level < 0)
                return;

        mutex_lock(&dev_priv->drm.struct_mutex);
        guc_log_late_setup(&dev_priv->guc);
        mutex_unlock(&dev_priv->drm.struct_mutex);
}

void i915_guc_log_unregister(struct drm_i915_private *dev_priv)
{
        if (!i915.enable_guc_submission)
                return;

        mutex_lock(&dev_priv->drm.struct_mutex);
        /* GuC logging is currently the only user of Guc2Host interrupts */
        gen9_disable_guc_interrupts(dev_priv);
        guc_log_runtime_destroy(&dev_priv->guc);
        mutex_unlock(&dev_priv->drm.struct_mutex);
}